A. Roux

Pneumocystis jirovecii Pneumonia in Patients with or without AIDS, France

Immunosuppressed patients without AIDS had longer time to treatment and a higher rate of death than did patients with AIDS.

Lymphopenia-Driven Homeostatic Regulation of Naive T Cells in Elderly and Thymectomized Young Adults

Reduced thymopoiesis and continuous mobilization of naive T cells into the effector–memory pool can lead to severe alterations of the naive T cell compartment. However, maintenance of the naive T cell population is essential to mount effective immune responses. Evidence of homeostatic regulation of naive T cells is currently debated in animal models. In humans, the situation remains unresolved, in particular with advanced age. In this study, we analyzed the CD4+ and CD8+ naive T cell compartments from elderly, young adults thymectomized during early childhood, and HIV-1–infected patients, which are characterized by T lymphocytopenia. We show a direct association between increased turnover and decreased frequency of naive T cells. Moreover, the IL-7–induced pathway was fully functional in naive T cells from elderly and young adults thymectomized during early childhood, who are characterized by elevated IL-7 plasma levels. Our findings support the establishment of homeostatic regulation of naive T cell proliferation in humans. This regulation is particularly active in lymphopenic hosts, such as elderly and thymectomized patients.

Lung transplantation from initially rejected donors after ex vivo lung reconditioning: the French experience

OBJECTIVES Only 15% of brain death donors are considered suitable for lung transplantation (LTx). The normothermic ex vivo lung perfusion technique is used to potentially increase the availability of high-risk lung donors. We report our experience of LTx with initially rejected donors after ex vivo lung reconditioning (EVLR). METHODS From April 2011 to May 2013, we performed EVLR for 32 pairs of donor lungs deemed unsuitable for transplantation and rejected by the 11 French lung transplant teams. After EVLR, lungs with acceptable function were transplanted. During the same period, 81 double-lung transplantations (DLTx) were used as controls. RESULTS During EVLR, 31 of 32 donor lungs recovered physiological function with a median PO2/FiO2 ratio increasing from 274 (range 162-404) mmHg to 511 (378-668) mmHg at the end of EVLR (P < 0.0001). Thirty-one DLTx were performed. The incidence of primary graft dysfunction 72 h after LTx was 9.5% in the EVLR group and 8.5% in the control group (P = 1). The median time of extubation, intensive care unit and hospital lengths of stay were 1, 9 and 37 days in the EVLR group and 1 (P = 0.17), 6 (P = 0.06) and 28 days (P = 0.09) in the control group, respectively. Thirty-day mortality rates were 3.3% (n = 1) in the EVLR group and 3.7% (n = 3) in the control group (P = 0.69). One-year survival rates were 93% in the EVLR group and 91% in the control group. CONCLUSIONS EVLR is a reliable and repeatable technique that offers a significant increase of available donors. The results of LTx with EVLR lungs are similar to those obtained with conventional donors.

Differential Impact of Age and Cytomegalovirus Infection on the γδ T Cell Compartment

γδ T cells represent a subset of unconventional T lymphocytes that are known for their reactivity against different pathogens and considered as intermediate mediators between adaptive and innate immunity. We provide in this paper further insights underlying the changes that affect the γδ T cell compartment with advanced age in humans. We show that both aging and CMV infection impact independently on the γδ T cell compartment. Most γδ T cells are significantly affected by age and present a decreased frequency in the elderly. The decline of the γδ T cell pool appears to be independent from the activity of the thymus, arguing in favor of an extrathymic site of γδ T cell production in humans. Of note, CMV infection, which is directly associated with the activation of the pool of Vδ2− γδ T cells, promotes nonetheless the inflation of this compartment throughout life. CMV seropositivity accentuates further the accumulation of highly differentiated lymphocytes in Vδ2− γδ T cell subsets with time, in contrast to Vδ2+ γδ T cells, which maintain a less differentiated phenotype. This is similar to the effect of CMV on αβ T cells and suggests that γδ T cells may vary in differentiation phenotype according to distinct stimuli or pathogens.

Clinical assessment for identifying causes of acute respiratory failure in cancer patients

In cancer patients with acute respiratory failure (ARF), early adequate therapy is associated with better outcomes. We investigated the performance of the DIRECT approach, which uses criteria available at the bedside at admission to the intensive care unit (ICU), to identify causes of ARF in cancer patients. This cohort study included cancer patients with ARF of determined aetiology. Associations of aetiological groups with the selected criteria were evaluated using correspondence analysis. 424 cancer patients were included: 201 (47%) with bacterial pneumonia, 131 (31%) with opportunistic infections and 92 (22%) with noninfectious disorders. Mechanical ventilation (both invasive and noninvasive) was needed in 328 (77%) patients, treatment for shock in 217 (51%) patients and dialysis in 82 (19%) patients. 142 (34%) patients died in the ICU. Correspondence plots showed that bacterial pneumonia was associated with neutropenia, solid tumour, multiple myeloma, <3 days since symptom onset, shock, unilateral crackles and unilateral radiographic pattern. Opportunistic infections were associated with steroids, lymphoproliferative disorders and haematopoietic stem-cell transplantation, whereas noninfectious disorders were associated with acute leukaemia The selected criteria are strongly associated with causes of ARF in cancer patients and could be used to develop an algorithm for selecting first-line diagnostic investigations and empirical treatments.

Coordinated expansion of both memory T cells and NK cells in response to CMV infection in humans

NK cells are key players in the fight against persistent viruses. Human cytomegalovirus (HCMV) infection is associated with the presence of a population of CD16+ CD56dim NKG2C+ NK cells in both acutely and latently infected individuals. Here, we studied the nature of these terminally differentiated NK cells in different human populations infected with HCMV: healthy donors stratified by age, thymectomized individuals, pregnant women suffering from primary CMV infection, and lung transplant patients. Both CD16+ CD56dim NK‐ and CD8 T‐cell phenotypes as well as functional capacities were determined and stratified according to age and/or CMV event. Similarly to T‐cell responsiveness, we observe an accumulation over time of NKG2C+ NK cells, which preferentially expressed CD57. This accumulation is particularly prominent in elderly and amplified further by CMV infection. Latent HCMV infection (without replication) is sufficient for NKG2C+ CD57+ NK cells to persist in healthy individuals but is not necessarily required in old age. Collectively, the present work supports the emerging concept that CMV shapes both innate and adaptive immunity in humans.

CMV driven CD8+ T-cell activation is associated with acute rejection in lung transplantation

Lung transplantation is the definitive treatment for terminal respiratory disease, but the associated mortality rate is high. Acute rejection of the transplanted lung is a key determinant of adverse prognosis. Furthermore, an epidemiological relationship has been established between the occurrence of acute lung rejection and cytomegalovirus infection. However, the reasons for this association remain unclear. Here, we performed a longitudinal characterization of CMV-specific T-cell responses and immune activation status in the peripheral blood and bronchoalveolar lavage fluid of forty-four lung transplant patients. Acute rejection was associated with high levels of cellular activation in the periphery, reflecting strong CMV-specific CD8(+) T-cell activity post-transplant. Peripheral and lung CMV-specific CD8(+) T-cell responses were very similar, and related to the presence of CMV in the transplanted organ. These findings support that activated CMV-specific CD8(+) T-cells in the lung may play a role in promoting acute rejection.

T Cells Promote Bronchial Epithelial Cell Secretion of Matrix Metalloproteinase-9 via a C-C Chemokine Receptor Type 2 Pathway: Implications for Chronic Lung Allograft Dysfunction

Chronic lung allograft dysfunction (CLAD) is the major limitation of long-term survival after lung transplantation. CLAD manifests as bronchiolitis obliterans syndrome (BOS) or restrictive allograft syndrome (RAS). Alloimmune reactions and epithelial-to-mesenchymal transition have been suggested in BOS. However, little is known regarding the role of allogenicity in epithelial cell differentiation. Primary human bronchial epithelial cells (BECs) were treated with activated T cells in the presence or absence of transforming growth factor (TGF)-β. The expression of epithelial and mesenchymal markers was investigated. The secretion of inflammatory cytokines and matrix metalloproteinase (MMP)-9 was measured in culture supernatants and in plasma from lung transplant recipients (LTRs): 49 stable, 29 with BOS, and 16 with RAS. We demonstrated that C-C motif chemokine 2 secreted by T cells supports TGF-β-induced MMP-9 production by BECs after binding to C-C chemokine receptor type 2. Longitudinal investigation in LTRs revealed a rise in plasma MMP-9 before CLAD onset. Multivariate analysis showed that plasma MMP-9 was independently associated with BOS (odds ratio [OR] = 6.19, p = 0.002) or RAS (OR = 3.9, p = 0.024) and predicted the occurrence of CLAD 12 months before the functional diagnosis. Thus, immune cells support airway remodeling through the production of MMP-9. Plasma MMP-9 is a potential predictive biomarker of CLAD.

Dichotomy in pulmonary graft-versus-host disease evident among allogeneic stem-cell transplant recipients undergoing lung transplantation

Allogeneic haematopoietic stem-cell transplantation (HSCT) has become a life-saving treatment option for numerous benign and malignant diseases, with more than 14 500 procedures being performed annually in Europe alone [1]. Late-onset noninfectious pulmonary complications (NIPCs) have emerged as the main hurdle to long-term survival, affecting up to 26% of HSCT recipients and conferring 2- and 5-year survival rates of 44% and 13%, respectively [2, 3]. Interstitial lung disease is a common, largely unrecognised feature of pulmonary GvHD after stem cell transplant http://ow.ly/DWP4307mO3i

High Emergency Lung Transplantation: dramatic decrease of waiting list death rate without relevant higher post-transplant mortality

Many candidates for lung transplantation (LT) die on the waiting list, raising the question of graft availability and strategy for organ allocation. We report the experience of the new organ allocation program, “High Emergency Lung Transplantation” (HELT), since its implementation in our center in 2007. Retrospective analysis of 201 lung transplant patients, of whom 37 received HELT from 1st July 2007 to 31th May 2012. HELT candidates had a higher impairment grade on respiratory status and higher Lung Allocation Score (LAS). HELT patients had increased incidence of perioperative complications (e.g., perioperative bleeding) and extracorporeal circulatory assistance (75% vs. 36.6%, P = 0.0005). No significant difference was observed between HELT and non‐HELT patients in mechanical ventilation duration (15.5 days vs. 11 days, P = 0.27), intensive care unit length of stay (15 days vs. 10 days, P = 0.22) or survival rate at 12 (81% vs. 80%), and 24 months post‐LT (72.9% vs. 75.0%). Lastly, mortality on the waiting list was spectacularly reduced from 19% to 2% when compared to the non‐HELT 2004–2007 group. Despite a more severe clinical status of patients on the waiting list, HELT provided similar results to conventional LT. These results were associated with a dramatic reduction in the mortality rate of patients on the waiting list.